(a) Field of the Invention
The present invention relates to a thin film transistor (“TFT”) array panel and a manufacturing method thereof. More particularly, the present invention relates to a TFT array panel and a method of manufacturing TFT array panels with a reduced number of masks.
(b) Description of the Related Art
Flat panel displays such as a liquid crystal display (“LCD”), an organic light emitting device (“OLED”), and an electrophoretic display includes several pairs of field generating electrodes and electro-optical active layers interposed there between. The LCD includes a liquid crystal layer as the electro-optical active layer, and the OLED includes an organic emission layer as the electro-optical active layer.
One electrode within each pair of field generating electrodes, i.e., a pixel electrode, is commonly connected to a switching element for transmitting signals to the pixel electrode, and the electro-optical active layer converts the electrical signals to optical signals to display images.
TFTs having three terminals are used as the switching elements in a flat panel display, and the flat panel display also includes gate lines for transmitting gate signals to control the TFTs and data lines for transmitting signals to be applied to the pixel electrodes.
Among TFTs, organic TFTs (“OTFTs”) using an organic semiconductor instead of an inorganic semiconductor such as silicon Si, have been vigorously researched.
Moreover, since an OTFT may be fabricated in the form of a fiber or a film due to the flexible characteristics of the organic material, it has been in the spotlight as a core element of a flexible display device.
The OTFT may be fabricated by a solution process such as inkjet printing, and therefore the OTFT may be easily applied to a large-sized flat panel display.
However, the OTFT has a different structure and manufacturing process from other TFTs, including an inorganic semiconductor, since the organic semiconductor has lower field effect mobility and lower stability than those of the inorganic semiconductor. In this case, the number of masks required to manufacture an OTFT increases, and so the manufacturing cost thereof is increased.